Mobile units, e.g. telephones, laptop computers, etc. are known to be able to roam in wireless networks between various locations. Still, while roaming through various networks and sub-networks they need to maintain their connectivity. Various aspects relating to this mode of operation were suggested by the IETF (“Internet Engineering Task Force”) and are described among others in a series of RFC (Request for Comment) documents. One of the well-known problems associated with wireless terminals, and in particularly with roaming mobile terminals, is the disconnection occurring due to any one of numerous reasons. The problem intensifies when dealing with such roaming mobile terminals, because of the fact that at the time of their disconnection they roam in a network, and as such, when they try to reconnect they have to undergo a full network re-entry procedure which includes their re-authentication through the various entities along the way and of course through the authenticating entity at their home network. This is an issue which the present invention seeks to avoid, by eliminating the full above described procedure when the mobile terminal gracelessly disconnects from the serving BS (e.g. signal lost) and tries to re-connect to a new (or even the old) BS, but without compromising on security requirements so that the integrity of the network security will not be breached.